This invention relates to a device for determining the diameters of circular objects such as coins.
In order to classify circular objects according to their diameters, it is necessary to determine the diameters. For instance, when it is required to classify coins different in monetary denomination and different in diameter, it is necessary to measure the diameters. In a coin sorting machine for sorting out a number of coins by means of coin sorting holes different in diameter which are provided separately according to the monetary denominations, a diameter determining device is known in the art in which counting coins separately according to the monetary denominations is carried out by optically determining the diameters of coins at a coin passageway which is located before the first coin sorting hole (the counting operation being not carried out near the respective coin sorting holes). More specifically, in the diameter determining device, a light source and a photo-electric converter are disposed on both sides of the passageway, respectively, so that the diameter of a coin is determined from the amount of light which is shielded by the coin when the latter reaches the detection position. However, with the device, it is necessary to use a position detecting sensor in order to accurately detect when the coin reaches the detection position. In this case, it is required in conveying coins that the coins are moved along one side of the passageway by using a roller or the like, and accordingly the conveying mechanism is unavoidably intricate.